It is known that antimony-containing metal oxide catalysts, specifically those comprising the oxides of antimony and at least one metal selected from the group consisting of iron, cobalt, nickel, tin, uranium, chromium, copper, manganese, titanium, and cerium are useful for the production of aldehydes and acids through oxidation of organic compounds, the production of dienes, unsaturated aldehydes and unsaturated acids through oxidative dehydrogenation, and the production of nitriles through ammoxidation. Japanese Patent Publication No. 19111/64, for example, discloses a useful catalyst for production of acrylonitrile through ammoxidation of propylene, comprising the oxides of antimony and iron, cobalt or nickel. It is described in U.S. Pat. No. 3,197,419 that a catalyst comprising the oxides of antimony and iron is useful for oxidation and ammoxidation of olefins. In addition, a catalyst comprising the oxides of antimony and tin is described in Japanese Patent Publication No. 14075/62 (corresponding to U.S. Pat. No. 3,152,170); a catalyst comprising the oxides of antimony and uranium, in Japanese Patent Publication No. 24367/65 (corresponding to U.S. Pat. No. 3,308,151); a catalyst comprising the oxides of antimony and manganese in U.S. Pat. No. 3,200,081; and a catalyst comprising the oxide of antimony and a metal selected from Cr, Co, Cu, Ni, or Ti in U.S. Pat. No. 3,340,291.
Attempts have been made to improve the above catalysts through addition of other components. For example, catalyst compositions comprising the oxides of antimony and iron, the oxides of antimony and tin, or the oxides of antimony and uranium, and the oxides of at least one element selected from the group consisting of vanadium, molybdenum and tungsten, and tellurium are proposed as multiply promoted antimony-polyvalent metal oxide catalysts in Japanese Patent Publication Nos. 2804/71 (corresponding to U.S. Pat. No. 3,668,147), 40985/72, and 19764/72.
These antimony-containing metal oxide catalysts, however, have various problems; for example, poor reproducibility in preparation of the catalysts, difficulty in preparing catalysts having high strength, and low operation efficiency in preparation of the catalyst. To overcome these problems, several improvements in preparation of the catalysts have been proposed, including those as described in Japanese Patent Publication Nos. 22476/67 (corresponding to U.S. Pat. No. 3,341,471), 3456/71, 3457/71, 18722/72 (corresponding to U.S. Pat. No. 3,657,155), and 18723/72 (corresponding to U.S. Pat. No. 3,686,138).
These methods, however, are not satisfactory from an industrial standpoint; that is, problems still remain to be solved in connection with, for example, satisfactory improvements in both activity and physical properties, and reproducibility. One of the problems is that in preparation of catalysts for use in a fluidized-bed reactor, as shown in Comparative Example 6 as described hereinafter, the density of the catalyst particles is increased. This adversely influences the state of the fluidized-bed catalyst during the reaction and in turn, the reaction. Furthermore, these catalysts give unsatisfactory yields of the desired product and other properties.